From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Tue, 9 Dec 2008 22:53:16 +0000 (+0100)
Subject: tracing/function-graph-tracer: add a new .irqentry.text section
X-Git-Tag: v2.6.29-rc1~586^2~12^3~3
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=a0343e823184070f55364d8359f832dcb33c57c7;p=linux-2.6-omap-h63xx.git

tracing/function-graph-tracer: add a new .irqentry.text section

Impact: let the function-graph-tracer be aware of the irq entrypoints

Add a new .irqentry.text section to store the irq entrypoints functions
inside the same section. This way, the tracer will be able to signal
an interrupts triggering on output by recognizing these entrypoints.

Also, make this section recordable for dynamic tracing.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S
index 46e05447405..1a614c0e6be 100644
--- a/arch/x86/kernel/vmlinux_64.lds.S
+++ b/arch/x86/kernel/vmlinux_64.lds.S
@@ -35,6 +35,7 @@ SECTIONS
 	SCHED_TEXT
 	LOCK_TEXT
 	KPROBES_TEXT
+	IRQENTRY_TEXT
 	*(.fixup)
 	*(.gnu.warning)
 	_etext = .;		/* End of text section */
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index eba835a2c2c..c61fab1dd2f 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -288,6 +288,16 @@
 		*(.kprobes.text)					\
 		VMLINUX_SYMBOL(__kprobes_text_end) = .;
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+#define IRQENTRY_TEXT							\
+		ALIGN_FUNCTION();					\
+		VMLINUX_SYMBOL(__irqentry_text_start) = .;		\
+		*(.irqentry.text)					\
+		VMLINUX_SYMBOL(__irqentry_text_end) = .;
+#else
+#define IRQENTRY_TEXT
+#endif
+
 /* Section used for early init (in .S files) */
 #define HEAD_TEXT  *(.head.text)
 
diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index 0b1dc9f9bb0..fe831412bea 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -114,6 +114,7 @@ my %text_sections = (
      ".text" => 1,
      ".sched.text" => 1,
      ".spinlock.text" => 1,
+     ".irqentry.text" => 1,
 );
 
 $objdump = "objdump" if ((length $objdump) == 0);